title: Subgroups of enlarged vestibular aqueduct in relation to SLC26A4 mutations and hearing loss.
abstract: OBJECTIVE
  To investigate possible association of hearing loss and SLC26A4 mutations with the subgroups of enlarged vestibular aqueduct (EVA) morphology in Japanese subjects with hearing loss.
  
  
  METHODS
  Retrospective multicenter study.
  
  
  METHODS
  Forty-seven subjects who had vestibular aqueduct with midpoint diameter >1 mm by computed tomography of the temporal bone were enrolled at multiple sites across Japan, and DNA samples and clinical data were collected. EVA morphology was classified into four subgroups by the pattern of enlargement: aperture, aperture and midpoint, midpoint, and borderline enlargement. Venous blood DNA samples were subjected to polymerase chain reaction-based direct sequencing of all exons and exon-intron boundaries of the SLC26A4.
  
  
  RESULTS
  Four novel SLC26A4 mutations were identified in the present study. SLC26A4 mutations were detected in almost all subjects with aperture, aperture and midpoint, and midpoint enlargement. In contrast, 71% of subjects with borderline enlargement had no SLC26A4 mutation. No significant difference was found in the distribution of truncating and nontruncating SLC26A4 mutations between the EVA subgroups. In addition, no significant correlation was observed between the EVA subgroups and hearing levels, incidence of hearing fluctuation, or progression of hearing loss.
  
  
  CONCLUSIONS
  Subgroups of EVA morphology were significantly correlated with the presence or absence of SLC26A4 mutation. In a subgroup analysis of subjects with SLC26A4 mutations, however, differences in the EVA subgroups were not correlated with SLC26A4 genotypes or characteristics of hearing loss.
  
  
  METHODS
  NA.
authors.affiliation: Department of Otolaryngology, National Hospital Organization Tokyo Medical Center, Tokyo, Japan; Department of Otorhinolaryngology, Inagi Municipal Hospital, Tokyo, Japan; Department of Otolaryngology, Keio University Hospital, Tokyo, Japan.
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Hideki
authors.initials: H
authors.lastname: Mutai
authors.forename: Atsuko
authors.initials: A
authors.lastname: Nakano
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Arimoto
authors.forename: Tomoko
authors.initials: T
authors.lastname: Sugiuchi
authors.forename: Sawako
authors.initials: S
authors.lastname: Masuda
authors.forename: Noriko
authors.initials: N
authors.lastname: Morimoto
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Noboru
authors.initials: N
authors.lastname: Ogahara
authors.forename: Akira
authors.initials: A
authors.lastname: Takagi
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Taiji
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Kaga
authors.forename: Kaoru
authors.initials: K
authors.lastname: Ogawa
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Matsunaga
mesh_terms: D000293:Adolescent; D000328:Adult; D001301:Audiometry, Pure-Tone; D001692:Biological Transport; D002648:Child; D002675:Child, Preschool; D004247:DNA / Q000235:genetics*; D004252:DNA Mutational Analysis; D018450:Disease Progression; D005260:Female; D005838:Genotype; D034381:Hearing Loss / Q000209:etiology* / Q000235:genetics / Q000378:metabolism; D006319:Hearing Loss, Sensorineural / Q000150:complications / Q000000981:diagnostic imaging / Q000235:genetics*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D012189:Retrospective Studies; D000076988:Sulfate Transporters; D013701:Temporal Bone / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D014723:Vestibular Aqueduct / Q000002:abnormalities* / Q000000981:diagnostic imaging; D055815:Young Adult
chemical_list: D026901:Membrane Transport Proteins; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters; D004247:DNA
keywords: DFNB4; Enlarged vestibular aqueduct; Pendred syndrome; SLC26A4; computed tomography; hearing loss